1.\" Copyright (c) 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)shutdown.8 8.2 (Berkeley) 4/27/95 29.\" $FreeBSD: src/sbin/shutdown/shutdown.8,v 1.12.2.5 2003/02/23 21:17:43 trhodes Exp $ 30.\" 31.Dd June 9, 2020 32.Dt SHUTDOWN 8 33.Os 34.Sh NAME 35.Nm shutdown , 36.Nm poweroff 37.Nd "close down the system at a given time" 38.Sh SYNOPSIS 39.Nm 40.Op Fl 41.Oo 42.Fl h | Fl p | 43.Fl r | Fl k 44.Oc 45.Oo 46.Fl o 47.Op Fl n 48.Oc 49.Ar time 50.Op Ar warning-message ... 51.Nm poweroff 52.Sh DESCRIPTION 53The 54.Nm 55utility provides an automated shutdown procedure for super-users 56to nicely notify users when the system is shutting down, 57saving them from system administrators, hackers, and gurus, who 58would otherwise not bother with such niceties. 59.Pp 60The following options are available: 61.Bl -tag -width indent 62.It Fl h 63The system is halted at the specified 64.Ar time . 65.It Fl p 66The system is halted and the power is turned off 67(hardware support required, otherwise the system is halted) 68at the specified 69.Ar time . 70.It Fl r 71The system is rebooted at the specified 72.Ar time . 73.It Fl k 74Kick everybody off. 75The 76.Fl k 77option 78does not actually halt the system, but leaves the 79system multi-user with logins disabled (for all but super-user). 80.It Fl o 81If one of the 82.Fl h , 83.Fl p 84or 85.Fl r 86is specified, 87.Nm 88will execute 89.Xr halt 8 90or 91.Xr reboot 8 92instead of sending a signal to 93.Xr init 8 . 94.It Fl n 95If the 96.Fl o 97is specified, prevent the file system cache from being flushed by passing 98.Fl n 99option to 100.Xr halt 8 101or 102.Xr reboot 8 . 103This option should probably not be used. 104.It Ar time 105.Ar Time 106is the time at which 107.Nm 108will bring the system down and 109may be the case-insensitive word 110.Ar now 111(indicating an immediate shutdown) or 112specify a future time in one of two formats: 113.Ar +number , 114or 115.Ar yymmddhhmm , 116where the year, month, and day may be defaulted 117to the current system values. 118The first form brings the system down in 119.Ar number 120minutes and the second at the absolute time specified. 121.Ar +number 122may be specified in units other than minutes by appending the corresponding 123suffix: 124.Dq Li s , 125.Dq Li sec , 126.Dq Li m , 127.Dq Li min . 128.Dq Li h , 129.Dq Li hour . 130.Pp 131If an absolute time is specified, but not a date, 132and that time today has already passed, 133.Nm 134will assume that the same time tomorrow was meant. 135(If a complete date is specified which has already passed, 136.Nm 137will print an error and exit without shutting the system down.) 138.It Ar warning-message 139Any other arguments comprise the warning message that is broadcast 140to users currently logged into the system. 141.It Fl 142If 143.Sq Fl 144is supplied as an option, the warning message is read from the standard 145input. 146.El 147.Pp 148At intervals, becoming more frequent as apocalypse approaches 149and starting at ten hours before shutdown, warning messages are displayed 150on the terminals of all users logged in. 151Five minutes before 152shutdown, or immediately if shutdown is in less than 5 minutes, 153logins are disabled by creating 154.Pa /var/run/nologin 155and copying the 156warning message there. 157If this file exists when a user attempts to 158log in, 159.Xr login 1 160prints its contents and exits. 161The file is 162removed just before 163.Nm 164exits. 165.Pp 166At shutdown time a message is written to the system log, containing the 167time of shutdown, the person who initiated the shutdown and the reason. 168Corresponding signal is then sent to 169.Xr init 8 170to respectively halt, reboot or bring the system down to single-user state 171(depending on the above options). 172The time of the shutdown and the warning message 173are placed in 174.Pa /var/run/nologin 175and should be used to 176inform the users about when the system will be back up 177and why it is going down (or anything else). 178.Pp 179A scheduled shutdown can be canceled by killing the 180.Nm 181process (a 182.Dv SIGTERM 183should suffice). 184The 185.Pa /var/run/nologin 186file that 187.Nm 188created will be removed automatically. 189.Pp 190When run without options, the 191.Nm 192utility will place the system into single user mode at the 193.Ar time 194specified. 195.Pp 196Calling 197.Dq Nm poweroff 198is equivalent to running: 199.Bd -literal -offset indent 200shutdown -p now 201.Ed 202.Sh FILES 203.Bl -tag -width /var/run/nologin -compact 204.It Pa /var/run/nologin 205tells 206.Xr login 1 207not to let anyone log in 208.El 209.Sh EXAMPLES 210Reboot the system in 30 minutes and display a warning message on the terminals 211of all users currently logged in: 212.Pp 213.Dl # shutdown -r +30 \&"System will reboot\&" 214.Sh BACKWARD COMPATIBILITY 215The hours and minutes in the second time format may be separated by 216a colon (``:'') for backward compatibility. 217.Sh SEE ALSO 218.Xr kill 1 , 219.Xr login 1 , 220.Xr wall 1 , 221.Xr nologin 5 , 222.Xr halt 8 , 223.Xr init 8 , 224.Xr reboot 8 225.Sh HISTORY 226A 227.Nm 228command was originally written by Ian Johnstone for UNSW's modified 229.At v6 . 230It was modified and then incorporated in 231.Bx 4.1 . 232